Abstract
Composite solid electrolytes including inorganic nanoparticles or nanofibers which improve the performance of polymer electrolytes due to their superior mechanical, ionic conductivity, or lithium transference number are actively being researched for applications in lithium metal batteries. However, inorganic nanoparticles present limitations such as tedious surface functionalization and agglomeration issues and poor homogeneity at high concentrations in polymer matrixes. In this work, we report on polymer nanoparticles with a lithium sulfonamide surface functionality (LiPNP) for application as electrolytes in lithium metal batteries. The particles are prepared by semibatch emulsion polymerization, an easily up-scalable technique. LiPNPs are used to prepare two different families of particle-reinforced solid electrolytes. When mixed with poly(ethylene oxide) and lithium bis(trifluoromethane)sulfonimide (LiTFSI/PEO), the particles invoke a significant stiffening effect (E′ > 106 Pa vs 105 Pa at 80 °C) while the membranes retain high ionic conductivity (σ = 6.6 × 10–4 S cm–1). Preliminary testing in LiFePO4 lithium metal cells showed promising performance of the PEO nanocomposite electrolytes. By mixing the particles with propylene carbonate without any additional salt, we obtain true single-ion conducting gel electrolytes, as the lithium sulfonamide surface functionalities are the only sources of lithium ions in the system. The gel electrolytes are mechanically robust (up to G′ = 106 Pa) and show ionic conductivity up to 10–4 S cm–1. Finally, the PC nanocomposite electrolytes were tested in symmetrical lithium cells. Our findings suggest that all-polymer nanoparticles could represent a new building block material for solid-state lithium metal battery applications.
Highlights
Solid-state lithium batteries (SSLBs) have the potential to extend the range of electric vehicles and enable large-scale storage for renewable energy
Single-ion nanoparticles were obtained in the form of a colloidal dispersion in water, commonly defined as latex, adapting a semibatch emulsion polymerization strategy reported in detail elsewhere.[19−21] Briefly, the reactor was initially charged with water, purged with a gentle flow of N2, and heated to 80 °C
Three streams were injected to the reactor: the first contained the main monomer and the cross-linker; the second contained the functional comonomer (LiMTFSI) and the reductant of the redox pair used to generate radicals; the third stream was the oxidant of the redox pair
Summary
Solid-state lithium batteries (SSLBs) have the potential to extend the range of electric vehicles and enable large-scale storage for renewable energy. Among the different types of solid electrolytes, composite electrolytes that combine several materials such as polymer matrixes, inorganic nanoparticles, nanofibers, organic solvents, ionic liquids, and salts are an emerging class.[4] This is due to the limitations commonly typically shown by polymer (low ionic conductivity and lithium transference number) or inorganic solid electrolytes (low mechanical properties and interfacial stability). Previous research on composite electrolytes of this type has focused on inorganic nanoparticles and polymeric nanofibers.[5] For example, inorganic nanoparticles have been used to immobilize or thicken liquid electrolytes, i.e., organic carbonates, glymes, or ionic liquids, while polymeric nanofibers such as cellulose nanofibers or electrospun PVDF nanofibers[6,7] have been used to mechanically reinforce electrolyte matrixes.[8,9] Inorganic nanoparticles have been dispersed into polymer electrolytes, such as poly(ethylene oxide), with the aim to increase mechanical properties and ionic conductivity due to the nanostructuration effect.[10−12] inorganic nanoparticles suffer from
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
